1. Field of the Invention
The present invention relates generally to substrate preparation systems and methods, and more particularly to apparatuses and methods for cleaning of disk-shaped substrates, including silicon wafers such as used in the fabrication of semiconductors, and aluminum, ceramic, plastic, glass and multi-component disks for data storage devices such as hard disk drives (HDD), compact discs (CD), digital video discs (DVD), and the like used in the computer, information and entertainment industries.
2. Description of the Related Art
The computer, information, and entertainment industries produce and consume countless disk-shaped substrates, principally silicon wafers, and aluminum, plastic, glass, or other multi-component disks. In the fabrication of semiconductors, silicon wafers are processed through multiple fabrication steps which can include repeated application and removal of variously conductive, non-conductive and semi-conductive materials before the resulting micro-circuits are complete and separated into individual dies. Aluminum, glass, and other composite disk substrates are typically over-coated with magnetic, optical, or magneto-optical materials in the fabrication of HDDs, CDs, DVDs, and other such products.
Substrates must be buffed, polished, etched, cleaned, and otherwise prepared repeatedly during the fabrication process. This is true for both wafer and disk substrates. In the semiconductor manufacturing industry, integrated circuit devices designed of more complex, and more precise multi-layered structures require highly clean and prepared surfaces. In the field of magnetic and optical media disks, ever-increasing density translates into exacting requirements for disk cleaning and preparation. Defects resulting from improper, incomplete, or insufficient substrate buffing, polishing, cleaning, or other preparation produces decreased yield and increased time and cost.
In the prior art, substrate preparation systems and methods typically implement a one-at-a-time process. Substrates may be processed through multiple iterations of buffing, polishing, and cleaning with successive process steps being progressively cleaner. Such processing typically involves the transfer of substrates from one process station to another. The dwell time, or time of actual buff, polish, scrub, etc., of a single substrate, is typically 2.5-5 seconds, with an upper limit of about 10 seconds. Transfer between stations consumes another 4-15 seconds. The prior art is inefficient, time-consuming, and gradually failing to meet the increasing demands of cleanliness requirements.
In view of the foregoing, there is a need for substrate preparation systems and methods that can be applied to the operations of substrate polishing, buffing, scrubbing, cleaning and otherwise preparing the surface of both wafer and disk substrates. The substrate preparation systems and methods need to produce a highly clean substrate required by current and future technological demands, and need to be able to produce greater volumes of highly clean substrates in a shorter production time, more efficiently and consistently.
Broadly speaking, the present invention fills these needs by providing a cascade scrubber system and method that can be configured for both wafer and disk applications. The cascade scrubber system and method incorporates a series or cascade of cleaning or substrate preparation zones in a single unit that can be configured for one or more parallel operations providing a continuous and multisubstrate operation that results in cleaner and more thoroughly prepared substrates in shorter period of time. It should be appreciated that the present invention can be implemented in numerous ways, including as a process, an apparatus, a system, a device or a method. Several inventive embodiments of the present invention are described below.
In one embodiment, an apparatus for processing a semiconductor wafer is disclosed. The apparatus for processing a semiconductor wafer includes two pairs of rollers configured to prepare the semiconductor wafer in a vertical orientation. A track is provided that is configured to support the semiconductor wafer in a vertical orientation between the two pairs of rollers, and a pair of guiding rollers is provided to transition the semiconductor wafer in the vertical orientation along the track between the two pairs of rollers.
In another embodiment, an apparatus for processing a semiconductor wafer is disclosed. The apparatus for processing a semiconductor wafer includes two pairs of brushes oriented horizontally and arranged longitudinally from each other, and configured to receive in between the pairs of brushes a vertically oriented wafer. A track is provided along the two pairs of brushes that is configured to provide a path for the vertically oriented wafer to transition in a rolling movement between the pairs of brushes.
In still a further embodiment, a cascaded wafer scrubbing apparatus is disclosed. The cascaded wafer scrubbing apparatus includes an array of brush pairs with the array including a plurality of rows of brush pairs. Each brush pair is horizontally oriented along each row of brush pairs, and a track is also provided along each row. The track is configured to support and transition a wafer in a vertical orientation between each of the brush pairs along each row.
In yet another embodiment, a method for preparing a semiconductor wafer is disclosed. The semiconductor wafer preparation method includes picking a wafer from a source and placing the wafer in a vertical orientation into a track. The method further provides the transitioning of the wafer along the track which is configured with pairs of brushes arranged longitudinally along the track. The method further includes the scrubbing of the surfaces of the wafer using each of the pairs of brushes as the wafer is transitioned along the track.
The advantages of the present invention are most notably the consistent production of highly clean semiconductor wafers in a shorter production time. The cascade design of the present invention provides multiple cleaning and other wafer processing operations in a single station or module, thus eliminating the time and resource consuming processes of wafer transfer between cleaning or other process stations.
Another advantage of the invention is the increased volume of wafer cleaning or other preparation. A single line of a cascade scrubber can sequentially clean a large volume of wafers in a shorter period of time by eliminating the station-to-station transfer time. The cascade scrubber, however, can be configured with multiple lines operating in parallel and yielding a significant increase in volume.
A further advantage is the consistent production of highly clean wafers. The present invention provides a cascade of cleaning stations arranged in a line that progresses from xe2x80x9cdirtierxe2x80x9d to xe2x80x9ccleanerxe2x80x9d in as many or few zones as the process and resources of the user demands. Further, the wafers are continuously fed through the progressively cleaner, cascade scrubbing system, and the xe2x80x9cdwellxe2x80x9d time, or time of actual buff, polish, scrub, or even etch or rinse, can be increased or decreased as circumstances and needs of the user dictate.
Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the present invention.